Projectiles are typically subjected to an extreme environment (15,000 g's and 20,000-60,000 psi) as they are launched from a cannon. As an example, “blow-by pressure” builds up along the side of the projectile. This pressure build-up often causes structural damage to the projectile which can be a critical safety concern. Therefore, the effects of the pressure build-up are usually addressed during development of the projectile by conducting tests to determine the pressure that the projectile is exposed to during launch.
One approach to conducting such pressure tests is by collecting data from pressure taps that are typically inserted into the side of the cannon tube. These pressure taps often cause damage to the cannon tube while providing discrete points of reference to establish a pressure profile from the perspective of the cannon tube. These single points of reference are analyzed and estimates are made to create corresponding pressure profile curves. These pressure profile curves usually do not provide enough accurate detail to properly characterize the blow-by pressure seen along the projectile body.
Another approach to conducting such pressure tests utilizes pressure sensors positioned within the projectile at discrete locations around the projectile. Positioning pressure sensors around the projectile in this manner provides data regarding blow-by pressure on the projectile. However, there is no correlation as to where the sensors are located on the instrumented projectile and where the maximum pressure is exerted on the projectile.
In addition, there are usually limitations associated with calibrating these types of sensors. As an example, these types of sensors typically need to be permanently embedded within the projectiles in order to allow the sensors to survive the extreme environments that they are exposed to during launch.